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Worst Case Climate Scenario Could Be Even Worse Than Thought

A picnic area at Assateague Island National Seashore after Hurricane Sandy. NPS Climate Change Response

When scientists set out to model the impacts of climate change, they use four different Representative Concentration Pathways (RCPs), which each represent a different possible radiative forcing, i.e.a total of human-caused greenhouse gas emissions measured in Watts per square meter, according to the Intergovernmental Panel on Climate Change (IPCC.)

The four different RPCs.IPCC

Each RCP also sets a different option for global temperature, rate of greenhouse gas emissions and total atmospheric greenhouse gas concentration by 2100, as G.P. Wayne explained in a summary for The Guardian..

The total greenhouse gas concentration (in parts per million of carbon dioxide equivalent) for each RCP.Ilinri

For example, when researchers predicted that low-lying atolls could be uninhabitable by 2030-2060, the earliest date is based on RCP8.5.

Now, a paper published Monday in Proceedings of the National Academy of Sciences suggests that RCP8.5 might not be bad enough. That is because researchers have underestimated the degree of uncertainty in calculating rates of economic growth on both a global and regional per capita basis. Greater uncertainty means that growth rates could be higher than projected, leading to higher greenhouse gas emissions. The study found that there is a 35 percent chance that global greenhouse gas emissions will therefore be worse than the levels predicted by RCP8.5 for 2100.

"The implication is that if we are producing more and consuming more, we must assume that emission rates will grow significantly faster than we thought," study co-author and assistant professor in the University of Illinois (U of I) Department of Agricultural and Consumer Economics Peter Christensen said in a U of I press release published by EurekaAlert! "In the absence of meaningful climate policy, higher baseline growth scenarios likely imply higher emissions growth around the world. The level of uncertainty revealed by this study will shift our modeling of physical and social processes related to changes in the climate and the baseline for policymaking," he said.

Just because RCP8.5 might be worse than predicted does not mean that humanity will actually follow a worse-case-scenario trajectory. That scenario assumes no action is taken on climate change, and global deals like the Paris agreement indicate that many countries are already moving to take action.

"We've already locked in a certain amount of climate policy," Glen Peters of the Center for International Climate Research in Norway, who was not involved with the research, said in a New Scientist article about the findings.

But higher economic growth might mean that the less catastrophic RCPs have underestimated both potential emissions and the amount of action required to combat them. "The results will also affect estimates of emissions pathways under a variety of policy scenarios," Christensen told The New Scientist.

The world of food and drug regulation was rocked earlier this month by the news of a change in leadership at the Food and Drug Administration. Commissioner Scott Gottlieb resigned and will step down in early April. His temporary replacement is Dr. Ned Sharpless, director of the National Cancer Institute.

On Wednesday the U.S. Environmental Protection Agency (EPA) announced the first 20 chemicals it plans to prioritize as "high priority" for assessment under the Toxic Substances Control Act. Given the EPA's record of malfeasance on chemicals policy over the past two years, it is clear that these are chemicals that EPA is prioritizing to ensure that they are not properly evaluated or regulated.

Strawberries top the Environmental Working Group's "Dirty Dozen" list of U.S. produce most contaminated with pesticides. DANIEL LEAL-OLIVAS / AFP / Getty Images

Which conventionally-grown fruits and vegetables in the U.S. are most contaminated with pesticides? That's the question that the Environmental Working Group answers every year with its "Dirty Dozen" list of produce with the highest concentration of pesticides after being washed or peeled.

A U.S. federal judge temporarily blocked oil and gas drilling on 300,000 acres of federal leases in Wyoming Tuesday, arguing that the Bureau of Land Management (BLM) "did not sufficiently consider climate change" when auctioning off the land, The Washington Post reported.

A report published Wednesday names the banks that have played the biggest recent role in funding fossil fuel projects, finding that since 2016, immediately following the Paris agreement's adoption, 33 global banks have poured $1.9 trillion into financing climate-changing projects worldwide.

Sriram Madhusoodanan of Corporate Accountability speaking on conflict of interest demand of the People's Demands at a defining action launching the Demands at COP24. Corporate Accountability

By Patti Lynn

2018 was a groundbreaking year in the public conversation about climate change. Last February, The New York Times reported that a record percentage of Americans now believe that climate change is caused by humans, and there was a 20 percentage point rise in "the number of Americans who say they worry 'a great deal' about climate change."